I recently replaced some injectors on my '90 DeVille 4.5 (runs great now), and besides the usual E52, I am getting a non-telltale E98 which reads as follows: "P/N to D/R ISC engaged problem". It seems like it's trying to tell me something is wrong with the Idle Speed Control when shifting out of Park or Neutral.
Can anyone interpret this code for me? Thanks in advance.
Matt

09-22-08, 01:31 PM

HUF

Re: E98 code on 4.5

Most likely your ISC motor is moving south... Does it make unusually loud ratcheting noise when you shut down the engine?

09-23-08, 09:12 AM

JCDSparks

Re: E98 code on 4.5

Quote:

Originally Posted by HUF

Most likely your ISC motor is moving south... Does it make unusually loud ratcheting noise when you shut down the engine?

Hey guys, sorry to jump in on this one but my '90 Deville shoots me the same code and my brother ( who is mechanin in Albany ,NY) said that after replacing the injectors or getting an ECM reset code(E52) that there is a procedure for recalibrating the ISC motor. I have the procedure in my book and will post it for you later this afternoon whenI return home form work.
But he also said if recal fails or doesn't hold the an ISC R&R is a must!! IT's enough to driv eyou to drink lol:alchi:
Thanks guys

09-23-08, 09:14 AM

JCDSparks

Re: E98 code on 4.5

Hey mdogg1950 and Huf why don't you guys shoot me a friend invite on here so us '90 deville owners don't have to sort through a crap load of stuff to get specific info and kinda help each other out ??

09-23-08, 10:24 AM

HUF

Re: E98 code on 4.5

Quote:

Originally Posted by JCDSparks

Hey guys, sorry to jump in on this one but my '90 Deville shoots me the same code and my brother ( who is mechanin in Albany ,NY) said that after replacing the injectors or getting an ECM reset code(E52) that there is a procedure for recalibrating the ISC motor. I have the procedure in my book and will post it for you later this afternoon whenI return home form work.
But he also said if recal fails or doesn't hold the an ISC R&R is a must!! IT's enough to driv eyou to drink lol:alchi:
Thanks guys

You will get E52 every time the battery is disconnected. Neither that nor injectors have anything to do with ISC. If you did not change ISC motor you do not need to "recalibrate" that. So, sorry either your brother was wrong in this particular case or you misunderstood something.

09-23-08, 03:53 PM

JCDSparks

Re: E98 code on 4.5

Quote:

Originally Posted by HUF

You will get E52 every time the battery is disconnected. Neither that nor injectors have anything to do with ISC. If you did not change ISC motor you do not need to "recalibrate" that. So, sorry either your brother was wrong in this particular case or you misunderstood something.

ALl right then I will check my book again!! Will post baack in a few I just gettin in and was check mail real quick the be back in a bit .

And for the record I suggested something about thew ISC recal to him and said he remembers hearing someting like that years ago, not try to be upset just politely explaining in case it sounded to harse sorry for that.
BRB
:rolleyes:

09-24-08, 05:13 AM

HUF

Re: E98 code on 4.5

Quote:

Originally Posted by mdogg1950

I recently replaced some injectors on my '90 DeVille 4.5 (runs great now), and besides the usual E52, I am getting a non-telltale E98 which reads as follows: "P/N to D/R ISC engaged problem". It seems like it's trying to tell me something is wrong with the Idle Speed Control when shifting out of Park or Neutral.
Can anyone interpret this code for me? Thanks in advance.
Matt

By the way, is that E98 code current or history? If you switch to N and press gas pedal , that code may be set. I would clear the codes and see if it returns.
A current code is one set during current ignition cycle (when you turn the ignition key ON).
A history code is one set during previous ignition cycles. It will be cleared automatically if it does not reappear in consecutive 50 ignition cycles.

10-08-08, 11:03 PM

mdogg1950

Re: E98 code on 4.5

Thanks everyone for the input. The E98 is new. Here's where it gets interesting: I had so much trouble with the idle (car would not idle down until after complete stop), that I disconnected the ISC a couple years ago. I set the curb idle by engine sound, and on a cold morning my right foot is the fast idle. I get better gas mileage and am not wearing my brakes out. Safer too. I hear this is a problem with these cars. It's called "idle sail".
Funny that code just showed up after my recent injector work??
Thanks again.
Matt

05-25-13, 05:19 PM

Presidentiallac

Re: E98 code on 4.5

Quote:

Originally Posted by mdogg1950

I recently replaced some injectors on my '90 DeVille 4.5 (runs great now), and besides the usual E52, I am getting a non-telltale E98 which reads as follows: "P/N to D/R ISC engaged problem". It seems like it's trying to tell me something is wrong with the Idle Speed Control when shifting out of Park or Neutral.
Can anyone interpret this code for me? Thanks in advance.
Matt

That DTC can come up when you shift from P to N going to fast or if you have your foot on the gas while doing it or from D to R. The computer is monitering to isc and it thinks that the isc is holding the rpms up. When really you have your foot on the gas while shifting. Erase the DTC and check if it comes up agin if so. The isc is getting stuck on your throttle cable is sticking.

05-29-13, 03:16 AM

HUF

Re: E98 code on 4.5

Quote:

Originally Posted by Presidentiallac

That DTC can come up when you shift from P to N going to fast or if you have your foot on the gas while doing it or from D to R. The computer is monitering to isc and it thinks that the isc is holding the rpms up. When really you have your foot on the gas while shifting. Erase the DTC and check if it comes up agin if so. The isc is getting stuck on your throttle cable is sticking.

This thread is 5 years old! :)

06-01-13, 12:03 PM

cadillac_al

Re: E98 code on 4.5

Quote:

Originally Posted by HUF

This thread is 5 years old! :)

And the OP was too cheap to buy another ISC which would have made the car more pleasant to drive.